Experts frequently point to Iraq’s past – colonial history, Saddam’s brutality, ethnic rivalries – to explain the current violence. But evidence from similar regimes indicates the causes may lie not in the echoes of the past, but in the long shadow cast by Iraq’s uncertain future.

“It is hard to fight and kill other people” – so said an Iraqi insurgent, struggling to explain to The Nation’s Christian Parenti why he had hung up his guns. Not to mention, US troops have overwhelmingly superior training, technology and firepower. Against this, planting roadside bombs is one thing, but attempting to take and hold towns – as Sunni and Shia militias have done in recent weeks – is quite another. For the Americans, it is frightening. It looks like a widening rebellion. But for the Iraqis, it is suicidal, and the militiamen have perished in the hundreds.

So why do it? No doubt many are motivated by religious zeal or rage at US troops. But it is no coincidence that the most violent groups have been those which expect to be excluded from power after the June 30th handover. The Sunnis in Fallujah have done the math and realize democracy will mean rule by the Shias. And rebellious Shia cleric Moqtada al-Sadr, whose militia seized Najaf, has been excluded from the political process in favor of more moderate figures.

This matters because in country after country, regardless of history, culture or geography, the presence of natural resource wealth has long fostered violence by politically excluded groups. The circumstances are varied, of course. The World Bank, in a famous study, tracked 161 countries between 1965 and 1999, looking at 47 civil conflicts. The insurgents ranged from disgruntled army factions to religious zealots to oppressed ethnic minorities. The one commonality was that countries which exported large amounts of primary commodities (such as oil and minerals) were “radically more at risk” of suffering civil wars.

The root of the problem for oil-rich countries will come as no surprise: the concentration of wealth and power in too few hands. To this, add: irrespective of stability. In most countries wealth is generated by society at large – for instance, via farming or private business – and any political violence jeopardizes this wealth by causing economic collapse. (Consider, for instance, the economic devastation wrought by the US civil war.) In resource-rich countries the wealth is generated by a tiny minority – e.g., oil workers; it is controlled by the government; and it diminishes hardly at all in the face of instability. (Africa’s oilfields have profitably pumped their way through more civil wars than one cares to remember.) In short, in countries like Iraq, political power is the most precious commodity, and violence does not destroy its value. So excluded groups will fight and die for it. And sitting governments will usually fight back.

This analysis may seem a bit bloodless. Moqtada al-Sadr’s militants do not seem that rational. Or that greedy. But for them, the concentration of power and wealth is reality, not theory. It is writ large in the absence of democracy in the Middle East. Governments that are richer than the people they rule rarely feel the need to share power. That is the history of Iraq, Iran, Saudi Arabia, Qatar, Libya. Excluded groups in such places soon realize the political game is always played for the highest possible stakes.

One would hope the US pledge to establish democracy in Iraq would make a difference. And there are, to be sure, a handful of resource-rich countries that have achieved long-term stability – the US, Norway and even Botswana, for example. But in each such case the key to success has been the establishment of functioning political and economic systems prior to the discovery of natural resource wealth. These functioning systems then distributed the resulting wealth and power widely and productively, defusing potential conflicts and producing stability.

Unfortunately, once the wealth has arrived, establishing democracy and markets becomes fiendishly difficult. The oil riches are the 800-pound gorilla lurking in the corner at any constitutional convention. Before the new systems can spread wealth and power around something usually goes wrong. The losers at the first election return to fighting, for instance. Almost inevitably, the gorilla gets loose and trashes the new system in its infancy.

If the US could convince Iraqis of their democratic, power-sharing, wealth-sharing future, it could defuse the violence that results from politics played for absolute stakes. Unfortunately, the example of other countries gives little help in this. There are few, perhaps no, successful cases of stable democracy introduced to people whose sole experience has been of oil despotism.

Undoubtedly, the suggestion by U.N. representative Lakhdar Brahimi, that Iraqi’s first, transition government be of apolitical bureaucrats committed to resigning from politics is a good one. An attempt to reduce the stakes. But convincing Iraq’s current, very political Governing Council to walk away from power will not be easy. Nor will convincing current and future insurgents to lay down their arms. As always, the oil wealth, the 800-pound gorilla, lurks in the shadows.

This article was originally published on Countryrisk.com, before I sold the website to Roubini Global Economics.